Filter module having a closure element

ABSTRACT

A closure element for sterile closure of connections, in particular connections of filter modules for dialysis, hemofiltration or ultrafiltration is described. A closure element with a simple design that provides a reliable seal is formed by having the closure element include a wall with an automatically closing slit-shaped indentation which when closed creates a germ-proof seal. The sealing element is used for sterile closure of connections of medical items, as well as for the medical items themselves.

RELATED APPLICATION

This application is a continuation of Applicants' U.S. patentapplication Ser. No. 09/441,182, filed Nov. 15, 1999, U.S. Pat. No.6,419,825, which is incorporated by reference herein as fully as if setforth in its entirety.

The present invention relates to a closure element for the sterileclosure of connections, and in particular to the closure of connectionswith filter modules for dialysis, hemofiltration or ultrafiltration.

DESCRIPTION OF RELATER ART

In the production of filter modules for dialysis, it is necessary tosterilize the filter modules after the actual manufacturing process andalso to protect the filter modules from external influences, such as thepenetration of microorganisms or dirt. One method of sterilizing filtermodules is the so-called in-line sterilization, where the interior areasof the filter module are cleaned, although the outside is notsterilized. Because open contact of the connections of the filter moduleduring or after the sterilization step must absolutely be avoided, thefilter module must be sealed in such a way that no contamination orsoiling of the interior of the filter module can occur duringsterilization or after removal from the sterilization device.

European Patent 352,540 describes a generic closure element consistingof two parts, with the first part of the closure element being attachedto the connection of the filter module or the dialyzer, while the secondpart of the closure element is accommodated in a receptacle space of thefirst closure element part. The device is arranged movably between anopen position and a closed position in this receptacle space. Thus, inthe open position, passage of the sterilization medium and sterilizationof all sealing surfaces and guidance surfaces can be achieved. In theclosed position, reliable sealing of the dialyzer can be achieved.Although such a closure element guarantees reliable sealing of thefilter module, it has the disadvantage of having a relatively complexstructure.

SUMMARY OF THE INVENTION

The present invention is an improvement upon a generic closure elementhaving a simple design that can reliably ensure a sterile closure.

The closure element includes a wall having a slit-shaped indentationthat closes automatically, and when closed forms a germ-proof closure.There are also fastening means that are adjacent to the wall, so theclosure element can be attached to a connection by these fasteningmeans. Such a closure element according to this invention has a simpledesign and provides a reliable and sterile seal of a medical object,such as a filter module, during and after sterilization, due to theautomatically closing slit-shaped indentation. When a suitableconnecting element such as a connection of a sterilization device or ofa dialysis machine is inserted, the slit-shaped indentation in theclosure element according to this invention is opened to fit the shapeof the connecting element.

When the connecting element according to this invention is removed fromthe closure element, after sterilization or treatment, the slit-shapedindentation closes automatically, thus preventing contamination of thesterilized area as well as leakage from the item sealed with the closureelement.

In an especially advantageous embodiment, the closure element has anessentially cylindrical shape, and the fastening means are formed by thecylindrical surface and the slit-shaped indentation, arranged on one ofthe end faces of the cylinder. The closure element forms a germ-proofconnection to the medical item by means of the cylindrical surface. Sucha cap-like design of the closure element has the advantage that thefluid supplied and removed flows along a simple linear path in a passagethrough the closure element. The development of dead zones can thus beeffectively prevented by an appropriate arrangement of the slit-shapedindentation. This design also prevents the mixing of different fluids,such as mixtures containing different active ingredients or medicines,that pass through the closure element.

Another embodiment of the present invention provides for a symmetricalclosure element design. Such a design not only simplifies themanufacture of the closure element, but also permits simple handling aswell as simple attachment and use of the closure element on thecorresponding connection of a filter module.

A preferred embodiment of the present invention provides for theslit-shaped indentation to have the shape of a cross or a star. Thisshape permits a very good flexibility and adaptation to connections ofvarious shapes and various diameters, in comparison with a simple lineardesign of the indentation. Another wall having an opening for thepassage of a fluid may be provided opposite to the wall with theindentation. In one example, the middle of the indentation may bealigned with the opening.

Another embodiment of this invention provides for the surface of theother wall extending around the opening to extend in a plane essentiallyperpendicular to the joining direction of the connecting element of theinvention. In this case, the closure element according to this inventionadditionally provides a tight connection of the connecting element, forexample between a dialysis machine and the filter module. A seal can beachieved by the connecting element having its end face sealably placedinside the opening of the other wall.

It is especially advantageous if the closure element according to thisinvention is a single piece, to provide advantages in the manufacturingprocess.

It is also especially advantageous if the wall with the indentation, andmore preferably advantageous if the entire closure element, is made ofplastic. In this manner, the flexibility and elasticity of the closureelement can be varied widely through the choice of a suitable plastic.In addition, compatibility with the fluid used or with a mixturecontaining various active ingredients can be achieved through the choiceof the plastic. The use of plastic for the wall of the closure elementhaving the indentation, or for the entire closure element, also has theadvantage that a simple and cost-effective manufacturing process canproduce a variety of different embodiments and designs of the closureelement. It is especially advantageous if the plastic is a siliconeplastic.

An advantageous embodiment includes a wall with the slit-shapedindentation in the closure element that has a spring element acting inthe radial direction. This yields the advantage that radial stressforces are reduced over the transverse direction in the path of thespring element. This results in a slit-shaped indentation in the wallhaving improved sealing properties.

In another embodiment of the present invention, the spring element canbe formed by recesses that alternate or are individually placed on thetop and/or bottom sides of the wall. The recesses may be partiallycircular.

It is especially advantageous if no spring element is provided in theareas of the wall extending in the longitudinal direction of theslit-shaped indentation. This design increases the radial force actingin the direction of the slit, which yields an especially tight closureof the slit-shaped indentation.

Another embodiment of the present invention provides for the slit-shapedindentation in the closure element to form a germ-proof closureresisting up to a pressure difference of about ±0.25 bar.

The present invention also concerns the use of a closure element for thesterile closure of connections of medical items. In a preferredembodiment, the medical item is a filter module for dialysis,hemofiltration or ultrafiltration, with the closure element being usedfor in-line sterilization of the filter module.

Another embodiment of the present invention provides for fastening meansof the closure element that permit the closure element to be placed onprojecting connections, or inserted into bushing-like connections.

The present invention also concerns a medical item with one or moreconnections for supplying and/or removing a fluid, with at least oneconnection being provided with a closure element according to thisinvention. The medical item may be a filter module for dialysis,hemofiltration or ultrafiltration.

It is especially advantageous if the closure element is designed in sucha way that its inside surface is connected by a germ-proof connection tothe outer surface of a projecting connection. It is also advantageous ifthe outside surface of the closure element is connected by a germ-proofconnection to the inside surface of a bushing-shaped connection.

Another embodiment of the present invention provides for at least twoconnections of the medical item having a closure element according tothis invention.

BRIEF DESCRIPTION OF THE DRAWING

Additional details and advantages of the present invention will now beexplained in greater detail on the basis of embodiments illustrated inthe figures. In the drawings:

FIGS. 1A and 1B: are longitudinal sections respectively through a firstembodiment of a closure element according to this invention, and througha corresponding recess in the housing to accommodate the closureelement;

FIGS. 2A and 2B: show sectional views respectively of the closureelement from FIGS. 1A and 1B, according to perspective A—A andperspective B—B;

FIG. 3: is a longitudinal section through the closure element of FIG. 1,during a sterilization process;

FIG. 4: is a longitudinal section through the closure element accordingto FIG. 1, during use to form a connection;

FIG. 5: is a top view of a closure element according to this inventionhaving spring elements according to a second embodiment;

FIG. 6: is a longitudinal section on line A—A through the closureelement as shown in FIG. 5, and

FIG. 7: is a longitudinal section through the closure element accordingto this invention as shown in FIG. 5, immediately before being connectedto a connecting element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 shows closure element 10, according to this invention, with walls12 and 14 being parallel. Both walls 12, 14 border a hollow cylindricalspace 20, which is also defined by the cylindrical surfaces which areconnected to walls 12, 14 and serve as fastening means. Walls 12 and 14are adjacent to the cylindrical surfaces of closure element 10, and meetit at a right angle.

Wall 14 has slit-shaped, automatically closing indentation 141 with acentral section 143. Wall 12 has a central opening 121 of circularshape. Opening 121 and central section 143 of indentation 141 in wall 14are aligned with one another, so that the present closure element can beused to connect linear connecting elements.

FIG. 1B shows a housing 20 having an opening 30, for example of a filtermodule, for accommodating closure element 10 according to thisinvention. Opening 30 preferably is cylindrical, and can accommodateclosure element 10 in a form-fitting manner. To achieve a reliableseating of the closure element 10 in the housing recess 30, the outsidediameter of closure element 10 preferably is slightly greater than theinside diameter of the housing recess 30. This also produces a reliableand germ-proof seal between the housing 20 and closure element 10.

FIG. 2 shows two views of sealing element 10 according to thisinvention, seen from perspectives A—A (FIG. 2A) and B—B (FIG. 2B) ofFIG. 1. The solid lines in FIG. 2 correspond to the visible contours ofclosure element 10, while the broken lines represent cut edges that arenot visible in the perspective shown. FIG. 2A shows closure element 10with wall 14 having the automatically closing slit-shaped indentation141 with a central section 143. The cylindrical surfaces of the hollowcylinder are represented in FIG. 2A by the outermost solid line 200 andthe broken line 202 offset toward the inside. FIG. 2B shows wall 12,opposite to wall 14. A circular central opening 121 is formed in wall12.

FIG. 2B shows the alignment of opening 121 and central section 143 ofslit-shaped indentation 141. Slit-shaped indentation 141 is shown as apartially broken line in FIG. 2B, because in the view selected there itis visible only inside opening 121.

FIG. 3 shows closure element 10 during a sterilization process. Theconnection of the sterilization device 204 is inserted from the left, asshown in FIG. 3, in such a way that it first touches wall 14. Withfurther insertion, the device deforms the elastic wall 14 so that theslit-shaped indentation 141, which is closed when not in use, widens andforms an opening for the sterilization medium flowing in and out. Themedium may be a liquid, gas or vapor. In the embodiment according toFIG. 3, a seal is formed by a sealing ring 30 on the sterilizationdevice, forming a seal over the housing accommodating closure element10.

A sterilization fluid can then pass through opening 141 into hollowspace 20 of sealing element 10, and into the annular area which extendsto gasket 30 in contact with the housing.

After liquid passes through slit-shaped indentation 141, which isdeformed to create an opening, it goes through opening 121 into the partto be sterilized, for example into a dialysis filter. After removing thesterilization device 204 at the end of the sterilization, wall 14 ofclosure element 10 deforms back to its original shape, so the openingcloses and forms again the slit-shaped indentation 141. Wall 14 thenseals the sterilized part tightly, thus preventing leakage and drippingof sterilization liquid, and also preventing penetration of unwantedsubstances and microorganisms.

FIG. 4 shows the closure element 10 according to the invention duringnormal use. A connecting element 206 is inserted through the slit-shapedindentation 141 in wall 14 until the end side of the connection is incontact with the side of wall 12 adjacent to hollow space 20 of closureelement 10. Depending on the diameter of the connecting element, theareas of wall 14 on both sides of slit-shaped indentation 141 can becurved in the direction of wall 12 as shown in FIG. 4. The fluidsupplied and removed then passes through the opening of the connectingelement and through opening 121 in wall 12, into and out of theconnected part, which could be, for example, a connected dialysisfilter. A tight and thus germ-proof connection is achieved due to thetight seal of the end side of the connecting element against the insideof wall 12. In addition, FIG. 4 illustrates how a linear passage for theliquid is obtained by aligning the connecting element 206 and closureelement 10, thus largely preventing unwanted dead zones in the passage.

At the end of the treatment, the connecting element 206 can beretracted, so that the portions of wall 14 return to their originalshape and again form a tightly sealed slit-shaped indentation 141, asillustrated in FIG. 2.

The embodiments illustrated in FIGS. 3 and 4 show that microorganismscan be prevented from passing through the connection duringsterilization or during the normal use of closure element 10.Furthermore, closure element 10 can easily be removed from thecorresponding housing recess 30, so that simple and inexpensivereplacement is possible. Thus, a sterile and hygienic connection of theparts to be connected can be achieved, and contamination of the fluidsconveyed can be prevented.

FIGS. 5 through 7 show a second embodiment of a closure element 10according to this invention. FIG. 5 shows a top view of the secondembodiment of closure element 10. Closure element 10 has a cylindricalshape, with an automatically closing slit-shaped indentation 141 in wall14 being visible on the end face in FIG. 5. Spring elements 145 arearranged in the areas extending radially out to the right and left ofslit-shaped indentation 141. The spring elements 145 can be, forexample, grooves formed in wall 14, that enable wall 14 to flex in aspring-like manner. These spring elements thus serve to reduce theradial tension forces in a transverse direction to the path of thespring element by reducing the cross section of wall 14.

As shown in FIG. 6, spring element 145 according to the presentembodiment comprises recesses 147 arranged alternatively in the top andbottom sides of wall 14. The recesses 147 reduce the cross-sectionalarea of wall 14, and lead to a desirable spring action and bending ofwall 14.

FIG. 5 illustrates that spring elements 145 do not extend completelyaround the slit-shaped indentation 141 in wall 14, but instead extendonly partially around it. In particular, spring elements 145 generallyare not provided in area 149 which extends in the longitudinal directionof indentation 141. Due to this design, the acting radial force isincreased in the closing direction, thus yielding an especiallyeffective and germ-proof closure of indentation 141. Such a design ofthe closure element 10 with spring elements 145 thus leads to improvedsealing properties of indentation 141 in wall 14.

Spring areas 145 may be incorporated in a closure element 10 made ofsilicone, according to the present embodiment, so that a pressuredifference of ±0.25 bar can be tolerated without indentation 141 losingits sealing effect.

FIG. 6 also shows a cylindrical jacket 210 extending perpendicularly towall 14, and serving as a fastening means with a peripheral projection131 formed on its end area. Projection 131 serves to engage closureelement 10 in a corresponding recess formed in a connecting element 42,shown in FIG. 7, and to secure it there reliably.

FIG. 7 shows a longitudinal section of the inserted closure element 10,according to the embodiment shown in FIGS. 5 and 6. Closure element 10is placed on the projecting connecting element 42 and is locked by meansof the peripheral projection 131.

If a pressure force, such as a force produced mechanically,pneumatically or hydraulically, is applied in the direction of the arrowin area 142 of wall 14, indentation 141 can be opened to a greater orlesser degree.

To ensure a sterile seal, it is necessary not only for slit-shapedindentation 141 in wall 14 to be sealed tightly, but also for aseal-tight connection to be established between closure element 10 andconnecting element 42. This is achieved because closure element 10includes a cylindrical surface forming the fastening means, designed tofit on the inside as well as the outside. As a result, the closureelement 10 ensures through the inside surface a germ-proof seal with theoutside surface of a projecting connecting element 42, and through theoutside surface with the inside surface of a bushing-like connectingelement.

1. A filter module having a plurality of connections for supplying orremoving a fluid from a device, at least one of said connectionscomprising: a closure element; a wall formed in the closure elementhaving an automatically closing slit-shaped indentation forming agerm-proof closure when closed; and means for fastening the closureelement to a connecting element disposed adjacent to the wall.
 2. Thefilter module according to claim 1, wherein the filter module isconfigured for one of dialysis, hemofiltration and ultrafiltration. 3.The filter module according to claim 1, wherein the closure elementcomprises one of an inside surface forming a germ-proof closure with theoutside surface of the connecting element, and an outside surfaceforming a germ-proof closure with an inside surface of a bushing-likeconnection.
 4. The filter module according to claim 1, wherein theclosure element is substantially cylindrical, the fastening mean includea cylindrical surface, and the slit-shaped indentation is formed on aend face of the cylindrical closure element.
 5. The filter moduleaccording to claim 1, wherein the closure element is symmetrical aboutan axis of the connection.
 6. The filter module according to claim 1,wherein the slit-shaped indentation is in the shape of a cross or astar.
 7. The filter module according to claim 1, further comprising asecond wall opposite to the wall having the indentation, the second wallhaving an opening for passage of a fluid.
 8. The filter module accordingto claim 7, wherein a middle portion of the indentation is aligned withthe opening.
 9. The filter module according to claim 7, furthercomprising a surface extending around the opening in the second wall,the surface lying in a plane substantially perpendicular to a joiningdirection of the closure element to the connecting element.
 10. Thefilter module according to claim 1, wherein the closure element isformed of one piece.
 11. The filter module according to claim 1, whereinthe wall and the closure element are made of plastic.
 12. The filtermodule according to claim 11, wherein the plastic is silicone.
 13. Thefilter module according to claim 1, wherein the wall comprises a springelement acting in a radial direction.
 14. The filter module according toclaim 1, wherein the slit-shaped indentation forms a germ-proof closureadapted to withstand a pressure difference up to about ±0.25 bar.